Top image: Aerial photograph of project site in its existing condition

Bottom image: Excerpt from project site plan showing relocated stream with habitat enhancements

Location

The work will occur at 18727 73^rd Avenue NE, a City-owned parcel on the west side of the street.

Schedule

Design Phase: 2023 – Q2 2025

Construction Phase: Q3-Q4 2025

• Note: The construction schedule includes 50 working days and is expected to be complete in early Fall 2025.

Project Description

• Scope of Work – Relocation and enhancement of approximately 450 feet of Muck Creek, a fish-supporting stream. Enhancements are aimed at improving habitat conditions for fish, especially salmonids, and include a new, meandering stream alignment with pool-riffle sequences, in-stream installation of woody debris, planting native trees and other plants, and expansion of site flood storage.
• Purpose – When construction projects cause impacts to surface water resources, environmental regulations require the project to provide a compensatory benefit (AKA “mitigation”) to the resource. This project serves as mitigation for stream impacts created by a separate City construction project. It will benefit salmonids and other fish that rely on Muck Creek for habitat by making the stream more supportive of this use. Specific improvements include:
  • Addition of woody material within the stream, which provides fish with refuge from predators and creates pockets of calmer water, which fish use for rest as they navigate the stream.
  • Removal of invasive plant species and replacement with native trees and other vegetation. This provides shade and organic litter that help reduce stream water temperature and provide a food source for fish, respectively.
  • Creation of pool-riffle areas within the channel and off-channel depressional areas fish use to avoid high flows, find food, and other purposes. The depressional areas will also expand the amount of flood storage volume at the project site, which will help alleviate flood impacts elsewhere in the Swamp Creek basin.
• What to Expect – During construction, people residing or traveling near the work site may experience the following impacts:
  • Traffic – The project will not require significant diversion of traffic on 73^rd Ave NE as construction will be confined to the City-owned parcel. Occasional, temporary disruptions to normal traffic flow may occur to accommodate deliveries of construction materials but these will not exceed 15 minutes in duration per incident.
  • Noise – typical construction noise and vibration such as that generated by heavy equipment (e.g. excavators, dump trucks, etc.) will be emitted at the work site during normal working hours, which occur Monday to Friday from 7:00 AM to 7:00 PM.